Piperazine compounds have any number of practical applications including the production of plastics, resins and other industrial work products. Piperazines may also be used in various end use applications such as in pesticides, automotive fluids and in pharmaceuticals.
One clear application for piperazine compounds is in the absorption of various contaminants often found resident in oil and gas streams. In specific, piperazine compounds and derivatives thereof such as N-alkyl-N-hydroxyethylpiperazine, N-hydroxyethylpiperazine and N,N-di(2-hydroxyethyl) piperazine (herein referred to as dihydroxyethyl piperazine or DiHEP) have been found useful due to their affinity for absorbing sulfur compounds and their ready reclamation for reuse in the absorption process (see, U.S. Pat. No. 5,098,681).
Generally, dihydroxyethyl piperazine is commercially available through processes such as, for example, the ethoxylation of piperazine (Gold-Aubert, Ph et. al. Helvetica Chimica Acta 1959, 42, 1156; Trejbal, Jiri, et. al. Reaction Kinetics and Catalysis Letters 2004, 82(2), 339), and the reductive alkylation and cyclization reaction of amino ethanolamine and diethanoamine in the presence of a hydrogen atmosphere and a hydrogenation dehydrogenation catalyst (see, U.S. Pat. No. 4,338,443).
Further, Rooney, U.S. Pat. No. 5,491,263 also discloses a method for the production of substituted ethylene diamines by reacting oxazolidinone with secondary amines or alkyl aryl amines.
One concern with these processes is that they generally produce a mixture of piperazine compounds along with the dihydroxyethyl piperazine. It is not uncommon for the ethoxylation process to produce piperazine, hydroxyethyl piperazine, and dihydroxy ethyl piperazine in mixture; among other compounds. This has been documented by others; Trejbal et al, Kinetics of Ethylenediamine and Piperazine Ethoxylation, Reaction Kinetics and Catalysis Letters (2004), 82(2) at 339-346 discusses the ethoxylation of ethylene diamine and piperazine.
Additionally, the selectivity of the processes described above suffers. Thus side products generated by these processes must be useful as a mixture or require the addition of extensive processing steps to purify the dihydroxyethyl piperazine must be applied.
Even still, there are many instances where dihydroxyethyl piperazine is preferred as more useful than a mixture of piperazine compounds. As such, there is a need for a process, and resulting composition, which produces dihydroxyethyl piperazine in an efficient commercially viable manner at a high level of purity.